France has confirmed that a French national was among the dead and has urged local authorities to clarify the circumstances of what happened on the island of Nosy Be on Thursday morning.

An Italian with both Italian and French passports was also killed, according to the Italian news agency ANSA.

Media in Madagascar say the attack happened after residents discovered a boy's mutilated body on a beach. The reports cite witnesses as saying the two Europeans were paraded through villages, beaten and burned on a beach.

Nosy Be is a major tourist destination near the northwest coast of Madagascar.

AP

Britain's Foreign Office advised against all travel to Nosy Be.

"British nationals currently living in Nosy Be should stay indoors and follow local security advice," it said in a statement. France and the United States and some other countries also advised their nationals to avoid the island.

France urged authorities to clarify the circumstances of what happened on the island.

There had been reports of "arson, looting and the mob killing of two foreign suspects held in police custody," sait the US Embassy in Madagascar.

The deadly riots were another blow to Madagascar's tourism industry, which has suffered because of political tension in the Indian Ocean country, one of the world's poorest. Madagascar, which has 20 million people, holds presidential elections on October 25 amid a protracted political crisis.

President Andry Rajoelina overthrew his predecessor in 2009, but Madagascar's special electoral court has barred him from running in the election as part of measures to restore stability.

Authorities in Madagascar appealed for calm and sent police reinforcements to the island.

Nosy Be, which means "big island" in Malagasy, the national language, has direct flights to some European destinations. Tourists who stray from the island's beaches are offered tours of rum distilleries, sugar cane fields, volcanic lakes and the colonial-era town of Hell-Ville.